The primary objective of the proposed controlled clinical trial is to determine whether local anesthesia attenuates the magnitude and duration of fluctuations in heart rate and transcutaneous oxygen associated with required, presumably painful medical procedures in the seriously ill newborn. Secondary goals are to 1) evaluate the effect of anesthesia during painful procedures on other physiological parameters such as respiratory rate, transcutaneous carbon dioxide, blood pressure, heart period and vagal tone; 2) identify individual differences in physiological response patterns of non-anesthetized neonates to painful procedures and evaluate how the patterns may relate to subsequent clinical course; and 3) evaluate the contribution of covariates (e.g., central nervous system dysfunction, previous procedures, severity of disease and gestational age) to physiologic response patterns of nonanesthetized infants undergoing invasive medical procedures. The proposed research will provide essential data on infant pain and ways of alleviating physiological fluctuations which could result in a significant reduction in neonatal morbidity and mortality. These studies will provide basic data in the area of psychobiology as such information pertains to clinical neonatology, pediatric behavioral medicine and child development. The long term goals are to gain a better understanding of infant pain and strategies for coping with pain in the seriously ill neonate and to provide objective information upon which responsible clinical recommendations to improve medical caregiving could be proposed.